Regional End‐Systolic Pressure‐Length Relationships Using a Volume‐Loading Technique in the Intact Pig Heart
Regional End‐Systolic Pressure‐Length Relationships Using a Volume‐Loading Technique in the Intact Pig Heart
复制标题
在完整猪心脏中使用容量加载技术的区域收缩末期压力-长度关系
作者：
W. Miller;A. Liedtke;S. Nellis;G. Copenhaver;L. Whitesell
本研究的目的是表征从压力段长度和压力直径关系得出的左心室收缩期弹性，并将所得的局部和整体弹性与已知的正性肌力变化进行比较。通过容量负荷技术，左心室压力段长度和压力直径在一系列连续搏动中发生变化，并且发现整个收缩期以 20 毫秒间隔的局部和整体关系是非线性的并表现出滞后现象。在八只动物中，迷走神经切断术、普萘洛尔（1.0 mg/kg）和阿托品（0.1 mg/kg）后出现局部滞后现象，并且无论心脏在相似的左心室收缩压范围内按容量（45-60 ml/sec）或按压力（部分主动脉闭塞）负荷，都存在局部滞后现象。弹性通过磁滞回线长轴的斜率线性近似。在每种情况下，弹性增加到最大值然后减少，从而定义收缩末期。在七只动物中，比较了用多巴酚丁胺（5-13 μg/kg/min）和普萘洛尔（6-51 μg/kg/min）治疗前后或诱导全身缺血后的最大弹性长度和直径。多巴酚丁胺使最大弹性直径增加了 37%； (P < 0.01) 和最大弹性长度增加 159%； （P<0.05）。普萘洛尔使最大弹性直径降低 27%； (P < 0.05) 和最大弹性长度增加 6%； （P = NS）。整体缺血（50％；冠状动脉流量减少）并没有显着改变最大弹性直径或长度。然而，随着缺血，最大弹性直径的直径截距增加了24%； (P < 0.025)，达到最大弹性长度的时间减少了 33%； （P<0.01）。比较所有干预措施，最大弹性长度和直径的百分比变化直接相关，但相关系数较低 (r = 0.49)。区域和整体弹性的这些差异表明区域和整体心肌力学之间存在复杂的关系，并且可能不一定反映收缩力的特定变化。
The purpose of this study was to characterize left ventricular systolic elastances as derived from pressure-segment length and pressure-diameter relationships, and to compare the resulting regional and global elastances to known changes in inotropy. Left ventricular pressuresegment length and pressure-diameter were varied in a series of consecutive beats by means of a volume-loading technique, and both regional and global relationships at 20-msec intervals throughout systole were found to be nonlinear and to exhibit hysteresis. In eight animals, regional hysteresis was present after vagotomy, propranolol (1.0 mg/kg), and atropine (0.1 mg/kg), and was present no matter whether hearts were loaded by volume (45–60 ml/sec) or by pressure (partial aortic occlusion) over a similar range of left ventricular systolic pressures. Elastance was linearly approximated by the slope of the major axis of the hysteresis loops. In each instance, elastance increased to a maximum and then decreased, thus defining end-systole. In seven animals, maximum elastance-length and -diameter were compared before and after treatments with dobutamine (5–13 μg/kg per min) and propranolol (6–51 μg/kg per min), or after induction of global ischemia. Dobutamine increased maximum elastance-diameter by 37percent; (P < 0.01) and maximum elastance-length by 159percent; (P < 0.05). Propranolol decreased maximum elastancediameter by 27percent; (P < 0.05) and maximum elastance-length by 6percent; (P = NS). Global ischemia (50percent; reduction in coronary flow) did not significantly change either maximum elastance-diameter or -length. However, with ischemia, the diameter intercept of maximum elastance-diameter increased by 24percent; (P < 0.025), and the time to maximum elastance-length decreased by 33percent; (P < 0.01). Comparing all interventions, the percent changes in maximum elastance-length and -diameter related directly but with a low correlation coefficient (r = 0.49). These differences in regional and global elastance suggest a complex relationship between regional and global myocardial mechanics, and may not necessarily reflect specific changes in contractility.
DOI：
10.1152/ajpheart.1983.245.1.h110
发表时间：
1983
期刊：
The American journal of physiology
影响因子：
--
作者：
Shroff,SG;Janicki,JS;Weber,KT
通讯作者：
Weber,KT
心脏形状的描述符和决定因素：概述。
DOI：
--
发表时间：
1981
期刊：
Federation proceedings
影响因子：
--
作者：
Weber,KT;Hawthorne,EW
通讯作者：
Hawthorne,EW